Iron Deficiency Anaemia in Women

One in 3 Australian women have been diagnosed with iron deficiency by age 50.This is largely caused by disorders of menstruation and pregnancy. In one study 11% of women (mostly premenopausal) without anaemia were nevertheless iron deficient. Menstrual loss of iron is approximately 1mg per day and a pregnancy, delivery and puerperium accounts for a loss of about 1000 mg.

The impact of anaemia in pregnancy includes higher rates of preterm delivery (Chinese study) spontaneous abortion, low birth weight and fetal death. Supplementation in Nepalese pregnancies with iron and folate has been shown to improve long term cognitive and intellectual function in offspring. Levels of haemoglobin below 60g/L have been associated with oligohydramnios, increased fetal cerebral vascular dilatation and abnormal fetal CTG patterns.

In spite of recommended iron supplementation a proportion of pregnant women still become iron deficient and require parenteral iron injections. This even applies to some women with thalassemia trait who would normally be regarded as in danger of iron overload. It is important to prove that all patients have a low ferritin before treatment.

The reasons for low iron levels in pregnancy include aversion or intolerance to oral iron, especially because of nausea or the inevitable constipation it can cause.

There is controversy about treating pregnancies with iron therapy because there are physiological reasons for much of the anaemia .This is caused by the haemodilutional effect of increased plasma volumes. Nevertheless the consequences of anemia in pregnancy and concerns about avoiding blood transfusion at delivery prompt obstetricians to intervene.

Similarly chronic menorrhagia may require parenteral treatment with iron as an alternative to blood transfusion, particularly as a pre-operative measure.  

Treatment with intramuscular iron -typically with repeated iron polymaltose injections (Ferrum HTM) -is time consuming, painful and almost inevitably stains the sites of injection. There is also a potential for infection.

The alternative is a total dose iron infusion whereby 1-1.5 g of iron polymalstose is administered intravenously over 1 to 3 hours as an outpatient procedure. Older iron compounds were associated with a significant (0.6%) risk of severe allergic reactions but this is not the case with iron polymaltose. Patient monitoring of vital signs such as pulse, blood pressure and temperature is undertaken during the infusion and the infusion is ceased should allergy occur.